This invention relates to thread control in textile machines, particularly knitting machines.
Textile machines generally process large numbers of individual threads at once, to convert these threads into textile material. If even one of these many threads breaks, is too loose (i.e. inadequately tensioned) or has knots, this will be immediately reflected in form of a defect in the textile being produced. Therefore, the threads must be monitored for the occurrence of one or more of these conditions and, where such a condition is detected, must result in immediate shut-down of the machine until the problem can be corrected.
Equipment for this purpose is known. It utilizes a tension arm which maintains the respective thread at an essentially constant tension in its passage through the machine. To detect the presence of knots, another arm is provided which is movable and past which the thread travels; a knot in the thread then entrains this movable arm, pivoting it about an axis and causing the machine to be shut down due to interruption of the motor circuit.
The prior-art equipment of this type is, however, not fully satisfactory in all applications, especially not with respect to its use in conjunction with threads (the term is intended to include filaments and yarns) of different thickness.